The mission of the Pharmacology Core is to provide analytical and pharmacokinetic support for other projects in the Program. Core staff will coordinate the collection and proper storage of all blood samples for the Program; perform measurements of serum or plasma concentrations of drugs and metabolites; and provide pharmacokinetic analyses for the laboratory projects. By establishing a central facility for planning and coordination of blood sampling protocols and the analytical processing of the numerous blood and other biological samples, this Core will minimize duplication of efforts and sample loss and to maximize success in obtaining the analytical and pharmacokinetic precision and information needed to accomplish the proposed research. High performance liquid chromatographic and gas chromatographic-mass spectrometric assays will measure plasma concentrations of 11 drugs and metabolites for the laboratory research and the clinical research projects. Core staff have established assays for morphine, morphine-3-glucuronide, morphine-6-glucuronide, sufentanil, hydromorphone, alfentanil, fentanyl, butorphanol, nalbuphine and buprenorphine. They will develop a proglumide assay early in the program and improve the buprenorphine assay. Overall, the Pharmacology core will assure dependable, high quality analytical support for the other projects in the Program.